Intro to Genetics
What is the central dogma of molecular genetics?
DNA is transcribed into RNA and RNA is translated into proteins
What charge does DNA have and what gives it that charge?
Negative; phosphate group
What is chromatin?
made up of DNA and proteins that is uncoiled and decondensed
What is the difference between the theory of preformation and the theory of epigenesis?
Theory of preformation stated that a gamete contains a complete miniature adult; while the theory of epigenesis stated that body organs are not initially present in the early embryo and developed later in life.
What did Chargaff’s proposed base composition state?
A=T and C=G; but A+T is not equal to C+G
What are nucleosomes? What larger structure do they form?
Nucleosomes are made up of a histone octamer; chromatid
Describe 2 differences between DNA and RNA.
DNA: double-stranded, thymine, OH- on the C'3 only
RNA: single-stranded, uracil, OH- on the C'2 and C'3
If a DNA sample requires a large amount of heat to denature it, what does it tell us about the base composition?
There is mostly C-G base pairs. Why?
What is the difference between Euchromatins and Heterochromatins
Euchromatids: (true) uncoiled and active
Heterochromatid: condensed and inactive
What is the difference between a nucleic acid, a nucleotide, a nucleoside, and a nitrogenous base?
Nucleic acid: DNA and RNA
Nucleoside: nitrogenous base and pentose sugar
Nucleotide: nitrogenous base, pentose sugar, and phosphate group
You are a scientist sequencing the DNA of a new species of rodent found deep in the Amazon rainforest. If you find that 15% of the base pairs present in the DNA are Guanine, what is the proposed percentage of Cytosine, Adenine, and Thymine in the genome?
Cytosine: 17%
Guanine: 17%
Adenine: 33%
Thymine: 33%
What are the 5 main types of histones? How do their pair to form tetramers?
Draw and label both a ribose and 2-deoxyribose sugar. Label where the nitrogenous base attaches and where the phosphate group may attach.
Describe the function of the following types of RNA.
mRNA: template for protein synthesis
tRNA: structural component of ribosome for protein synthesis
rRNA: carry amino acids for protein synthesis
What are the 3 types of chemical modifications, what enzyme is responsible for each, and what do they do?
Acetylation: Histone acetyltransferase; addition of a acetyl group
Methylation: Methyltransferase; addition of a methyl group
Phosphorylation: kinase; addition of a phosphate group